Plymouth Rubber Co. v. Minnesota Mining & Manufacturing Co.

321 F.2d 151, 138 U.S.P.Q. (BNA) 344
CourtCourt of Appeals for the First Circuit
DecidedJuly 15, 1963
DocketNos. 6040, 6042
StatusPublished
Cited by3 cases

This text of 321 F.2d 151 (Plymouth Rubber Co. v. Minnesota Mining & Manufacturing Co.) is published on Counsel Stack Legal Research, covering Court of Appeals for the First Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Plymouth Rubber Co. v. Minnesota Mining & Manufacturing Co., 321 F.2d 151, 138 U.S.P.Q. (BNA) 344 (1st Cir. 1963).

Opinion

WOODBURY, Chief Judge.

This is another chapter in what the court below aptly called a “litany of litigation” over Reissue Patent No. 23,843 dated June 29, 1954, of original Patent No. 2,559,990 for “Insulating Tape” issued on July 10, 1951, to Oace and others and by them assigned to Minnesota Mining and Manufacturing Company, a Delaware corporation of St. Paul, Minnesota. Once ferreted out the determinative issue on these appeals becomes relatively simple. But to drive the quarry out of its burrow we must analyse the patent and review this and other litigation between the parties over it.

On August 3, 1954, Minnesota brought suit against Sears, Roebuck and Company in the Middle District of North Carolina for infringement of its reissue patent by selling insulating tape manufactured by the plaintiff-appellee herein,. The Plymouth Rubber Company, Inc., a; Massachusetts corporation with its principal place of business in Canton in that Commonwealth. Plymouth intervened in¡ that suit as a party defendant and conducted the defense of its customer.1 On the next day, August 4, 1954, Minnesota, filed two similar suits, one in the Eastern District of Missouri against another Plymouth customer, which Plymouth actively defended, but in which it did not. formally intervene, and another in the-Northern District of Illinois against. [153]*153Plymouth and six of its customers. Both of these suits were stayed on representations by Minnesota that the North Carolina cases would dispose of the respective controversies without the necessity for trial, and the North Carolina cases in due course went to trial. In that litigation the district court, finding the facts and making the conclusions of law tendered by Minnesota, entered a decree on June 12, 1956, that its patent was valid and infringed, enjoined Sears and Plymouth from further infringement and referred the question of Minnesota’s damages to a master.2 On Plymouth’s appeal the United States Court of Appeals for the Fourth Circuit reversed and remanded. Sears, Roebuck & Company v. Minnesota Mining & Manufacturing Company, 243 F.2d 136 (C.A.4, 1957), petition for rehearing and motion to reopen denied, 249 F.2d 66 (C.A.4, 1957), cert. denied, 355 U.S. 932, 78 S.Ct. 413, 2 L.Ed.2d 415 (1958).

The decisions of the court of appeals in the above case define the issue in the one before us. To understand those decisions, however, we must first turn to the patent itself.

The patented product is a stretchable adhesive plastic tape designed primarily for use by electricians for covering splices in electrical conductors. The problem which Oace and his associates set out to solve, and apparently solved, was to plasticize a tape backing of polyvinyl chloride in order to make it stretchable and retractable (elastic) in such a way that it would remain in “permanent equilibrium” with a pressure-sensitive adhesive coating. The patentees say in their specification that they obtained their unique and valuable results “by utilizing an insulating tape in the form of a relatively thick but easily stretchable and highly elastic pressure-sensitive adhesive tape comprising a well-bonded, water-insoluble, non-corrosive, normally tacky and pressure-sensitive adhesive coating on a plasticized vinyl chloride polymer film which is in permanent equilibrium with the adhesive.” They say that by “permanent equilibrium” they mean “that the pressure-sensitive adhesive layer neither softens (becomes ‘pasty’) nor loses tackiness (becomes non-adherent) on prolonged contact with the backing or film layer.” Then the pat-entees go on to say:

“In order to secure permanent equilibrium between backing and adhesive, we employ with the vinyl chloride polymer a combination of modifiers including a substantial but minor amount (not to exceed about 20 parts per 100 parts of the vinyl polymer) of a low molecular weight liquid plasticizer such as dioctyl phthalate [or DOP] together with a substantially equal or somewhat greater amount of a high molecular weight resinous type plasticizer, the amount of the latter in any event being sufficient, together with the liquid plasticizer, to provide the desired degree of stretch in the final film.” (Italics supplied.)

The patentees describe a material known to the trade as “Paraplex G-25” as “a preferred example of a suitable resinous type plasticizer.” But they say:

“While resinous or high molecular weight modifiers such as ‘Paraplex G-25’ are themselves capable of producing the desired degree of strength, stretch and elasticity in vinyl chloride polymer films, and furthermore are generally classed as ‘non-migrating’ or ‘permanent’ type modifiers or plasticizers, it is sur[154]*154prisingly found that these materials do not provide for permanent equilibrium of adhesive and backing as herein defined. Instead, it has been shown that pressure-sensitive adhesives in prolonged contact with highly stretchable and elastic films consisting solely of vinyl polymer and resinous modifier lose a great deal, if not all, of their initial tackiness or pressure-sensitivity.”

Further emphasizing the necessity for the use of the two types of plasticizers, the patentees say that while the adhesive coating on a tape made from a film of the vinyl chloride polymer plus a resinous plasticizer and a liquid plasticizer in the relative proportions of 100:29.5:17.6 proved to be in “permanent equilibrium” with the backing: “On the other hand, adhesives coated on films plasticized with from 40 to 70 parts of ‘Paraplex G-25' and in the absence of the dioctyl phtha-late [or DOP, the low-molecular-weight liquid plasticizer mentioned above] were soon found to become deficient in tackiness.”

The United States Court of Appeals for the Fourth Circuit in the case cited above construed the claims which it said were typical, that is, claim 1 of the original patent and claim 6 for its reissue, in the light of the specification as covering the use of two separate and distinct kinds of plasticizers, one liquid and the other resinous, which the court said: “ * * * are two well defined and distinctive types of plasticizers, as the language of the specification indicates, which are not only well recognized by the trade but are characterized by substantial differences in chemical composition.” Then, finding that Plymouth was using only Paraplex G-40, which it said was a resinous plas-ticizer similar to Paraplex G-25 but less expensive, as the plasticizer for its polyvinyl chloride film, the court held that Plymouth had not infringed for the reason that even though it obtained the pat-entees’ result it did so by omitting one element covered by the claims of the patent. Wherefore it reversed and remanded.

On Minnesota’s petition for rehearing and motion to reopen on the ground of newly discovered evidence, the court of appeals wrote the second opinion cited above reiterating its previous decision that the patent taught that to manufacture the patented elastic, adhesive, insulating tape it was necessary to use both a resinous type and a liquid type plasticizer.

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321 F.2d 151, 138 U.S.P.Q. (BNA) 344, Counsel Stack Legal Research, https://law.counselstack.com/opinion/plymouth-rubber-co-v-minnesota-mining-manufacturing-co-ca1-1963.